Exposure apparatus and exposure method for use in forming a pattern of a semiconductor device

Abstract

An exposure apparatus for exposing a photoresist film formed on a semiconductor substrate includes a plurality of reticle stages on which respective reticles can be supported at the same time. The reticles can be selectively and hence, successively, positioned along the optical axis of the apparatus that extends from the light source of the apparatus to a substrate stage. One region of the photoresist film is exposed to light directed through the first reticle. Then the second reticle stage is aligned and another region of the photoresist film is exposed to light directed through the second reticle.

1. An exposure apparatus for exposing selected portions of a photoresist film formed on a semiconductor substrate, said apparatus comprising:
 a light source that generates light of a wavelength that will react with the photoresist film when the photoresist is exposed to the light;  
 a substrate stage configured to support the substrate;  
 a reticle stage system interposed between said light source and said substrate stage with respect to an optical axis of the apparatus extending from said light source to said substrate stage, said reticle stage system including a plurality of discrete reticle stages each configured to support a respective reticle thereon, each of said reticle stages being selectively positionable in the path of said optical axis while the others of said reticle stages are disposed out of the path of said optical axis such that reticles supported on said reticle stages can be irradiated in sequence with light from said light source, whereby respective regions of the photoresist film can be successively exposed to light from said light source passed through the reticles supported by said reticle stages, respectively, without removing either of the reticles from the reticle stage on which it is supported;  
 a first reticle supported on one of said reticle stages and bearing a main shot pattern designed for exposing the photoresist film at an inner region of the substrate;  
 a second reticle supported on another of said reticle stages and bearing a partial shot pattern that includes only part of the main shot pattern and designed for exposing a portion of the photoresist film adjacent an outer peripheral edge of the substrate; and  
 a reduction-projection lens interposed between said reticle stage system and said substrate stage with respect to said optical axis of the apparatus so as to project an image formed by incident light thereon onto the photoresist film on a reduced scale.  
 
   
   
     2. An exposure method for use in manufacturing a semiconductor device, said method comprising:
 loading a first reticle and a second reticle on a first reticle stage and a second reticle stage, respectively, the first reticle bearing a main shot pattern designed for exposing a portion of photoresist film at an inner region of a substrate, and the second reticle bearing a partial shot pattern that includes only a part of the main shot pattern and designed for exposing a portion of the photoresist film adjacent an outer peripheral edge of the substrate;  
 subsequently aligning the first reticle stage with a selected portion of the photoresist film at the inner region of the substrate and directing light from a light source through the first reticle and onto the selected portion of the photoresist film at the inner region while the second reticle is in a standby state in which the second reticle is not illuminated by light from the light source, thereby exposing the selected portion of the photoresist film at the inner region to the light such that an image of the main shot pattern borne by the first reticle is transcribed onto the photoresist film at the inner region; and  
 subsequently aligning the second reticle stage with a selected portion of the photoresist film adjacent the outer peripheral edge of the substrate and directing light from said light source through the second reticle and onto the selected portion of the photoresist film adjacent the outer peripheral edge of the substrate while the first reticle is in a standby state in which the second reticle is not illuminated by light from the light source, thereby exposing the selected portion of the photoresist film adjacent the outer peripheral edge of the substrate to the light such that an image of the partial shot pattern borne by the second reticle is transcribed onto the selected portion of the photoresist film adjacent the outer peripheral edge of the substrate.  
 
   
   
     3. The exposure method of  claim 2 , wherein said aligning of the first reticle stage with the selected portion of a photoresist film at the inner region of the substrate comprises setting the first reticle stage in an alignment position at which the first reticle stage is disposed in the path of an optical axis extending between the light source and a substrate stage that supports the substrate, and said aligning of the second reticle stage with the selected portion of the photoresist film adjacent the outer peripheral edge of the substrate comprises switching the first and second reticle stages such that the second reticle stage is moved to said alignment position and the first reticle stage is moved from said alignment position to a standby position out of the path of the optical axis. 
   
   
     4. A method of forming a pattern of a semiconductor device, said method comprising:
 loading a first reticle and a second reticle on a first reticle stage and a second reticle stage, respectively, the first reticle bearing a main shot pattern designed for exposing a portion of photoresist film at an inner region of a substrate, and the second reticle supported bearing a partial shot pattern that includes only part of the main shot pattern and designed for exposing a portion of the photoresist film adjacent an outer peripheral edge of the substrate;  
 subsequently aligning the first reticle stage with a selected portion of the photoresist film at the inner region of the substrate and directing light from a light source through the first reticle and onto the selected portion of the photoresist film at the inner region while the second reticle is in a standby state in which the second reticle is not illuminated by light from the light source, thereby exposing the selected portion of the photoresist film at the inner region to the light such that an image of the main shot pattern borne by the first reticle is transcribed onto the photoresist film at the inner region;  
 subsequently aligning the second reticle stage with a selected portion of the photoresist film adjacent the outer peripheral edge of the semiconductor substrate and directing light from said light source through the second reticle and onto the selected portion of the photoresist film adjacent the outer peripheral edge of the substrate while the first reticle is in a standby state in which the second reticle is not illuminated by light from the light source, thereby exposing the selected portion of the photoresist film adjacent the outer peripheral edge of the substrate to the light such that an image of the partial shot pattern borne by the second reticle is transcribed onto the selected portion of the photoresist film adjacent the outer peripheral edge of the substrate;  
 subsequently developing the photoresist film to form a photoresist pattern; and  
 etching the resultant structure comprising the substrate using the photoresist pattern as a mask.  
 
   
   
     5. The method of  claim 4 , wherein said aligning of the first reticle stage with the selected portion of a photoresist film at the inner region of the substrate comprises setting the first reticle stage in an alignment position at which the first reticle stage is disposed in the path of an optical axis extending between the light source and a substrate stage that supports the substrate, and said aligning of the second reticle stage with the selected portion of the photoresist film adjacent the outer peripheral edge of the substrate comprises switching the first and second reticle stages such that the second reticle stage is moved to said alignment position and the first reticle stage is moved from said alignment position to a standby position out of the path of the optical axis.